Sex and Age Differences in Glucocorticoid Signaling After an Aversive Experience in Mice
Author Information
Author(s): Li Yun, Zhang Bin, Yang Youhua, Su Ping, Samsom James Nicholas, Wong Albert H. C., Liu Fang, Fendt Markus
Primary Institution: Beijing Institute of Brain Disorders
Hypothesis
The timing of glucocorticoid release relative to traumatic memory formation is important and may differ by sex and age.
Conclusion
The study shows that corticosterone levels spike after an aversive experience and then drop below baseline levels, with variations based on sex and age.
Supporting Evidence
- Conditioned mice showed significantly more freezing behavior compared to controls, indicating effective fear memory formation.
- Corticosterone levels increased significantly over time in conditioned animals compared to controls.
- Female conditioned mice had significantly higher corticosterone levels than males at later time points after conditioning.
- Aged male mice had significantly lower corticosterone levels compared to adult males.
- Hydrocortisone treatment increased GR phosphorylation in a concentration-dependent manner.
Takeaway
When mice experience something scary, their stress hormone levels go up quickly and then drop down lower than normal, and this can be different for boys and girls or young and old mice.
Methodology
The study used fear conditioning in mice to measure serum corticosterone levels over time and examined GR phosphorylation and localization in HEK 293T cells.
Potential Biases
The blood harvesting procedures could elevate glucocorticoid levels, potentially influencing the results.
Limitations
The study relies on animal models that do not fully capture the psychological complexities of PTSD, and blood sampling procedures may induce stress responses.
Participant Demographics
Male and female C57BL/6J mice aged 6–8 weeks and an additional group of aged (64-week-old) mice were used.
Statistical Information
P-Value
p<0.00001
Confidence Interval
[95CI: 10.6; 18.9]
Statistical Significance
p<0.00001
Digital Object Identifier (DOI)
Want to read the original?
Access the complete publication on the publisher's website